The present invention relates to joint assemblies and arrangements for a railway bridge. A railway bridge is employed where a section of track must be repeatedly and reversibly raised and lowered with respect to another, stationary track section, so as to move a section of track, typically to allow for the passage of a ship through a waterway over which the bridge extends.
Typically, railroad bridge components require secure positioning of the constituent track sections when in the closed position so as to maintain a continuous and uniform wheel path as the railroad track endures repetitive impact and stress, as well as extreme inertial forces attendant to lateral movement of the wheels, especially in cases where the run up to the bridge is not straight.
The adjoining rail of a railway bridge assembly includes a tapered rail portion of the bridge approach section which typically terminates into a tapered end point for mating with a correspondingly shaped rail portion of the movable or lift portion of the rail bridge.
Because such rail bridge joints comprise portions that must be repeatedly moved with respect to one another to be engaged and disengaged, the rail portions must be repeatedly and securely moved from an engaged position, re-registered in an engaged position, and held in place in a guarded condition, such that the wheel remains on the tread-bearing surfaces as it proceeds through the bridge joint region.
In addition, rail bridge joints experience considerable wear due to the repeated contact between the moving wheels and the wheel engaging surfaces of the guard rail. These rail guards are designed to capture the wheel flange and direct it through the bridge joint region.
In prior art arrangements, rail bridge joints used a multiple piece arrangement to support a stock rail held between guard plates. Examples of such arrangements are shown in U.S. Pat. No. 6,672,516, which is hereby incorporated herein by reference and over which the present invention represents an improvement.
Such rail guard arrangements also carry the risk of derailment because their constituent assembly pieces would be subject to dislodgement over time, causing insecurity in the wheel's path.
Accordingly, it is desirable to provide a rail bridge arrangement that allows for secure and reliable repetitive disengagement and re-engagement of the constituent bridge portions, while providing a uniform, secure wheel path that distributes load and reduces wheel and guard wear, all while extending the service life of the constituent parts.
The embodiments of the invention described herein address the shortcomings of the prior art.